Y Pattern valve

Abstract

A valve of the Y pattern is disclosed which is useful for stopping gas flow in a vacuum system. The valve has particularly good sealing characteristics needing moderate pressures to seal in a uranium hexafluoride environment. Heretofore an environment of uranium hexafluoride required high sealing pressures to be developed at the valve seat.

I claim: 
     
       1. A Y pattern valve for controlling a gas flow, comprising: a valve body having;   a first inner cylindrical chamber having an inlet port and an outlet port for said gas flow;   a second inner cylindrical chamber intersecting said first inner cylindrical chamber at an oblique angle, said second inner cylindrical chamber having a diameter substantially greater than the diameter of said first inner cylindrical chamber in order to provide ledge means for supporting;   valve seat means disposed at said intersection and on said ledge means; and   a substantially rectilinear valve stem coaxially disposed within said second inner cylindrical chamber and having affixed thereto inner terminal valve seal means, whereby inwards axial movement of said valve stem causes said valve seal means to engage said valve seat means so that said gas flow is controlled;   said valve seal means comprising a terminal flexible and resilient valve seal member and a valve plug disposed between the terminus of said valve stem and said valve seal member, said valve plug being mounted to the terminus of said valve stem, said valve seal member being mounted to said valve plug;   said valve seat means having a sharp angled outer edge which engages said valve seal member, so that a portion of said valve seal member rolls over the outer edge or lip of said valve seat means and flows along the inclined surface of said valve seat means, to provide a wiping of said valve seat means by said valve seal member, whereby any solid particulate matter which has accumulated is removed, and so that the collection of any solid particulate matter on said valve seat means is minimized;   together with a bearing washer and a dished washer, said bearing washer being coaxially positioned on the surface of said valve seal member between said valve seal and said valve plug, said dished washer being coaxially positioned between said bearing washer and said valve plug, with the concave side of said dished washer facing said bearing washer;   so that when said valve seal means engages said valve seat means, said valve seal member enters the interior of said valve seat means, and said dished washer is caused to flatten out, so as to prevent said valve stem from jamming said valve seal member into said valve seat means;   and together with a vacuum sealing closure bellows, said bellows extending coaxially and concentrically about said stem and between said valve plug and a backing plate portion of said valve body, said backing plate portion being disposed at the outer end of said second inner cylindrical chamber and extending transversely to said stem, said vacuum sealing closure bellows providing closure sealing against vacuum loss while permitting axial movement of said stem and appurtenances thereto, with one end of said bellows being attached in a gas-tight manner to said valve plug, and the other end of said bellows being attached in a gas-tight manner to said backing plate portion of said valve body.   
     
     
       2. The Y pattern valve of claim 1, wherein said valve body is aluminum. 
     
     
       3. The Y pattern valve of claim 2, wherein said oblique angle is 45°. 
     
     
       4. The Y pattern valve of claim 3, wherein said valve seat means comprises a valve seat made of stainless steel. 
     
     
       5. The Y pattern valve of claim 4, wherein said valve seat is brazed or cemented to said aluminum body. 
     
     
       6. The Y pattern valve of claim 1, wherein said valve seal means comprises a valve seal made of teflon. 
     
     
       7. The Y pattern valve of claim 1 in which the valve seat means and the valve seal member are circular. 
     
     
       8. The Y pattern valve of claim 1 in which the solid particulate matter comprises uranium hexafluoride. 
     
     
       9. The Y pattern valve of claim 1 in which each end of the bellows is attached to its respective valve element by soldering. 
     
     
       10. The Y pattern valve of claim 1 in which the valve seal member is rotatably mounted to the valve plug. 
     
     
       11. The Y pattern valve of claim 1 in which "O" rings are provided within the valve body and between the elements of the valve, so that said elements may be detached from the valve body and then re-attached, to provide a vacuum tight assembly and for vacuum-tight sealing purposes. 
     
     
       12. The Y pattern valve of claim 1 in which the valve body is provided with a passageway which extends from and substantially transverse to the valve stem, to a vacuum source, so that on leakage of the vacuum space due to material failure or the like, any gas tending to fill the space adjacent the valve stem is removed by said vacuum source. 
     
     
       13. The Y pattern valve of claim 12 in which at least the outer portion of the passageway is threaded.